E-mail messages are widely used today for the purpose of communicating between users throughout the world. While many private e-mail systems exist, most messages are exchanged over the Internet, in an environment that is neither private nor confidential. E-mail messages are transferred from one user to another via a plurality of servers, and therefore they can be intercepted and read by unauthorized persons.
Two main approaches exist nowadays to the solution of this problem. The first involves the encryption of the message and/or of its attachments, using a common program, with an encryption key agreed upon. This method has the disadvantage of requiring that both users use the same encryption software, and that the encryption/decryption key be agreed between them beforehand. Given the large number of encryption programs, different users must use more than one different encryption program, which is inconvenient and cumbersome.
The other approach is the establishment of a “secure communication channel”. In this approach two users communicate freely between them through this channel, and they each can read the other's messages that are decrypted at their PC level, without the need to decide on a common decryption key for each message and to communicate the same to each other. However, this method has the disadvantage of requiring the opening of a specific communication channel between two users, and is therefore not flexible and simple to use.
The prior art methods also do not take into account the fact that most e-mail messages should enjoy some degree of privacy, but do not necessarily need to be strongly encrypted. The average user is uncomfortable about having his e-mail read by unauthorized persons, but it is not the general rule that e-mail messages contain top secret information.
The art has so far failed to provide a simple and convenient method by means of which two users can communicate between them by e-mail, while maintaining a reasonable degree of privacy of their communication, without the need for either opening a specific communication channel, or for agreeing before each message on a common encryption/decryption key.
It is therefore an object of this invention to provide such a system and method, by means of which privacy of the e-mail communication between any two users of the system can be maintained, even if they have not agreed beforehand on a common key, and even if they do not know one another.
It is another purpose of this invention is to provide such a method and system which are simple and convenient to operate.
It is yet another object of the invention to provide a system and method for maintaining the privacy of e-mail messages, which does not require complicated operations by the user.
Other purposes and advantages of this invention will appear as the description proceeds.